It is well known that some abdominal surgery may result in the formation of a faecal or urinary stoma and that the contents of the intestine or bladder will flow from the stoma outside the control of the patient. This will also be the case when a fistula develops between an internal organ and the abdominal surface or when an abdominal (or other) wound site breaks down allowing leakage of fluid from within the cavity. In all such cases it will be necessary to provide the patient with a means of collecting the waste material; this usually takes the form of a pouch or bag which is commonly called an "ostomy" bag.
The material to be collected is often corrosive to the skin of the patient and protection must be provided to prevent leakage around the stoma. In order to protect this area of skin, it is commonplace for the patient to apply to the skin a suitable covering which is often a gelatinous ring of a material the base of which is Karaya gum. These rings are sometimes separate items over which the collection bags also fit, or, sometimes, the rings are actually incorporated as part of the construction of a collection bag. There are considerable variations in the size of the stoma from patient to patient and it is therefore necessary for manufacturers of ostomy products to provide a significant range of protective rings of varying diameters. An object of the present invention is to provide a way of avoiding the need to supply such a range of rings, and provide a wider ringe of variations to the size of the aperture of the ring.